THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

[16:30:00] JAKE TAPPER, CNN: Are you going to have buses to get people out in bad weather? Have you trained your supporters in public speaking?

COREY LEWANDOWSKI, DONALD TRUMP'S CAMPAIGN MANAGER: Well, so you know, again, it's a misconception. It's really not that difficult to go on caucus. You have to be at a location at a specific time and listen to people make some speeches, and you can write down the name Trump on a piece of paper. It's a secret ballot. You write the name down and then you're all done. You're in and out in an hour.

And I think that people who are waiting in line for hours upon hours in the freezing cold to listen to his great message across this great state, they're going to do that, and they're going to come out in droves (ph). And you know, I think you're going to see a record turnout or hopefully a record turnout because people are finally engaged and excited about someone who they know can fundamentally change a broken Washington, D.C.

JAKE TAPPER, ANCHOR: So much of Mr. Trump's strength that we've seen has been branding. He's an excellent brander, whether it's himself, as a winner, or Jeb Bush as somebody who's low energy, et cetera. What happens to his winner brand if he doesn't win Iowa? Are you concerned at all about that?

LEWANDOWSKI. We'll, I'm not concerned about that. You know, your poll that came up today has us up 11 points in Iowa which is a great honor. He's up 20 points in the Hampshire, 32 points in the State of Florida, you know, 20 points in North Carolina.

I think that people are out and they realize that they want a strong leader. And look, a lot of people would say, "Hey, it'd be great to finish in second place in Iowa." The American people don't want to be in second place anymore. They want to be in first place. And we're going to compete as hard as we can for every single vote in this great state so that we hopefully will have the privilege of winning the Iowa caucus.

I know a lot of people will say, "Wow, that's a bold prediction." But look, it's time to be bold in our country. It's time to make sure America is placed first again. And why try and compete for second place when we should compete for first. And that's exactly what we'll do here in Iowa. TAPPER: I was on Twitter just a few minutes ago and I saw Mr. Trump has taken a swipe at my colleague, Alisyn Camerota from "New Day", who's an excellent journalist and a lovely person. And I just -- I wonder, you know, it's not going to get any easier if he actually becomes the nominee and becomes the president. At some point, is he going to stop tweeting especially criticisms at journalists?

LEWANDOWSKI: Well I think, you know, it's fair to say that the mainstream media, and I hate to say that, you know, they're biased obviously. Now, you've been to his rallies and they refuse to show the crowd, they refuse to capture how many people are there honestly. You know, the only time they want to talk about it is if protests are happens. So, you know, I think a lot of times, the mainstream media is very dishonest. I think he's the only candidate who's willing to hold them accountable and call them out when he doesn't think they're being fair.

TAPPER: All right, well I don't think I would characterize her that way, but I appreciate you answering the question. Corey Lewandowski, thanks so much. We'll see you in Iowa.

LEWANDOWSKI: Thank you.

TAPPER: More brand new polls ahead showing Hillary Clinton in an unusual position, the underdog, in both of the first two states. Now, she's swinging at Bernie Sanders. That story, next.

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[16:36:45]

TAPPER: Welcome back to "The Lead." More now in our politics leads. Stunning news from Iowa, a new CNN poll number show Hillary Clinton has gone from a lock to win the Hawkeye State to possibly, possibly destined to wake up in 12 days, having suffered another crushing loss in that state, except, unlike in 2008, New Hampshire, this time, might not be able to throw her a lifeline. A CNN/WMUR poll in the Granite State shows Clinton getting trounced by Senator Bernie Sanders from neighboring Vermont by 27 points.

CNN Senior Political Correspondent, Brianna Keilar is in Nashua, New Hampshire where Senator Sanders is speaking right now.

Brianna, Hillary Clinton has been launching a very aggressive attack against Sanders today.

BRIANNA KEILAR, CNN SENIOR POLITICAL CORRESPONDENT: That's right. She has been and they've been going back and forth. Bernie Sanders, behind me right now, talking about poverty. He's here in New Hampshire, four stops today, trying to shore up support in what is his most likely early contest win.

You mentioned that poll right now. He is leading Hillary Clinton according to that poll by about 2 to 1. It's a big, big lead here in New Hampshire, and so we're seeing this new volley of political attacks between these two candidates. KEILAR: Hillary Clinton doing something she wouldn't for the first several months of her campaign, calling out Bernie Sanders by name.

(BEGIN VIDEO CLIP)

HILLARY CLINTON, PRESIDENTIAL CANDITATE (D): Senator Sanders and I share many of the same goals, but we have different records and different ideas about how to drive progress.

(END VIDEO CLIP)

UNIDENTIFED FEMALE: In Iowa, painting the democratic socialist from Vermont as extreme and unrealistic.

(BEGIN VIDEO CLIP)

CLINTON: In theory, is it enough? A president has to deliver in reality.

(END VIDEO CLIP)

UNIDENTIFED FEMALE: But the once presumed democratic nominee is fighting off an insurgent push by Sanders who is delighting in the change of fortunes.

(BEGIN VIDEO CLIP)

BERNIE SANDERS, PRESIDENTIAL CANDIDATE (D). Today, the inevitable candidate does not look quite so inevitable as she did eight and a half months ago.

(END VIDEO CLIP)

UNIDENTIFED FEMALE: Taking a page out of Donald Trump's playbook, Sanders emphasizing his standing in New Hampshire polls.

UNIDENTIFED FEMALE: The latest CNN/WMUR poll in the Granite States shows Sanders with big leads and hypothetical match ups against Trump and Ted Cruz. Clinton also beats Trump and Cruz, but her margins are much narrower.

Sanders is out with an evocative new ad set to air in Iowa, Friday, where he's opened up a lead in the latest CNN/ORC poll, and a profile in "People" magazine where his now wife Jane describes how he proposed to her after a year-long breakup.

As Sanders focuses on his softer side, Clinton's e-mail controversy continues to dog her, after a letter from an independent government inspector revealed her e-mails contained information about highly classified defense and intelligence programs. Clinton, defending herself on NPR.

(BEGIN VIDEO CLIP)

CLINTON: As the state department has confirmed, I never sent or received any material marked classified. And that hasn't changed in all of these months.

(END VIDEO CLIP)

UNIDENTIFED FEMALE: She's hitting Sanders on National Security, an area where voters give her much higher marks.

(BEGIN VIDEO CLIP)

CLINTON: Senator Sanders doesn't talk very much about foreign policy. But when he does, it raises concerns because sometimes it can sound like he hasn't really thought it through.

(END VIDEO CLIP)

[16:40:11]

KEILAR: Clinton specifically, there Jake, referring to Sanders having said that he was open to working with Russia and Iran in fighting ISIS in Syria. What was Sanders report? He took a trip down memory lane, slamming Clinton for her Iraq war vote that arguably cost her the nomination in 2008.

Sanders, of course, behind me, this is his third of four events today. Hillary Clinton, despite really trailing him in the polls here, is back in New Hampshire tomorrow. She'll have a full day of three events, Jake.

TAPPER: All right, Brianna Keilar in Nashua, New Hampshire. Thanks so much.

Clinton's biggest backer, her husband, former president Bill Clinton is reportedly sounding the alarm about her campaign strategy. Sources telling Politico that President Clinton has been pestering his wife's campaign manager almost daily, telling him they need to forget about Iowa and refocus on other states such as Florida, Illinois, Ohio and Texas.

Joining me now to talk about it, Hillary Clinton's primary battle, National Press Secretary for the Clinton campaign, Brian Fallon. Sir, thanks for coming on today.

BRIAN FALLON, NATIONAL PRESS SECRETARY, HILLARY FOR AMERICA: Hi Jake.

TAPPER: According to this Politico report, it sounds like President Clinton has a lot of concerns about the strategy.

FALLON: I don't think that that report is accurate. And I think President Clinton checks in regularly. He's out on the trail, as you know, for us. I think he's very proud of the organization that we've built, not just in Iowa and New Hampshire, but across the March states.

We have a volunteer driven organization on the ground there. We're quite confident that in the support levels that we see across those march states. We plan for a close race all along. And as a result, have multiple paths to the nomination.

I think with Senator Sanders, there are appropriate questions being raised about the prospect, if he were the nominee, and that's why you see him very uncomfortably having to cite polls in a sort of Trump like manner. But actually, I don't think that those polls mean much because whereas with Hillary Clinton, you have a very tested person, someone that's gone through the ringer, has faced the republican attacks. With Senator Sanders scrutiny is just starting to be applied.

TAPPER: Well, let's talk about one of the attacks that you personally launched on a conference call earlier today. You and Jake Sullivan, one of Secretary Clinton's advisers on foreign policy, saying that there were serious questions to ask about Bernie Sanders position when it comes to Iran. What are the questions to be asked?

FALLON: So, last Sunday night at the democratic debate, an answer to a question from Andrea Mitchell, Senator Sanders stood on the debate stage and said that he believed that we should seek warmer relations with Iran, and specifically said that he thinks that we need to formally normalize relations with Iran.

Now, there is no bigger advocate of smart diplomacy than Hillary Clinton. During her tenure at the state department, she laid the ground work for the historic nuclear deal that was struck last year with that country. But she said at the time, when the deal was announced, that we need to take a distrust and verify approach, that we can't mistake this agreement for signaling an entrance to -- towards a warmer relations with Iran.

They are still a state sponsor of terrorism. They are still sworn to wanting to wipe out Israel. And so, it was very dangerous and a grave underestimation of Iran that he would say that. In the last couple of days since that debate when Senator Sanders has been asked about that statement, he's refused to defend it, reiterate it, or in any way expound on it.

TAPPER: Right.

FALLON: So, I think the question really needs to be asked, was that just a matter of him not understanding the question, or does he really stand by that position? And if so, he needs to explain why.

TAPPER: We're running out of time. I just want to ask you about Secretary Clinton, that NPR interview that you heard in Brianna's piece. She said, she's never sent or received anything marked classified. The candidate's entire defense seems to be pinned to on that word, on that one word, marked classified. It seems very clear from the intelligence community that some of the material was classified, whether it was marked that way or not. FALLON: No. That's actually not the case, Jake, because we know that last August, when this inspector general who leaked this letter or who --

TAPPER: Well, we don't know that he leaked that letter.

FALLONT: Correct. I should say that he --

TAPPER: He sent a letter to the senate intelligence committee.

FALLON: Yes, and it's quite inappropriate that he even sent that letter to Congress while this justice department review is going on. So, did he leak the letter directly? Probably not. Did he have every expectation, probably, that that letter was going to be leaked by the Members of Congress to whom he sent it it? Probably.

In any case, he made this allegation back in August, calling two of those e-mails top secret. That finding has been challenged by the state department from the very beginning. And in fact, there was a Politico report two months ago that suggested that the rest of the intelligence community was inclined to side against this inspector general. I think that disagreement is the exact reason why this inspector general inappropriately decided to send this letter to Capitol Hill, probably with the hope, if not the outright attempts, to have it be leaked.

TAPPER: Well, you're stating a lot there that are -- and these facts not an evidence if were on a court or law. But I appreciate you advocating for your boss, Brian Fallon. Thanks so much. Good luck sir, surrounding this storm.

FALLON: Thank you.

TAPPER: Next Monday night in Iowa, an event only on CNN exactly one week before Iowa chooses Bernie Sanders, Hillary Clinton and Martin O'Malley will go face-to-face with some of the voters of Iowa in a CNN democratic presidential town hall live from Des Moines.

Our buddy Chris Cuomo is going to moderate. It is a unique opportunity for Iowans to ask questions of the three Democrats just before they go and cast their votes. That's next Monday night at 9:00 p.m. Eastern live only on CNN.

Officials accused of covering up a toxic water crisis in Flint, Michigan. Now new e-mails just released show who knew what and when. That's next.

Plus, he once called Putin a pedophile and guess what, then he wound up dead. Now a new investigation says this former Russian spy was probably ordered killed by Putin himself.

(COMMERCIAL BREAK)

TAPPER: Welcome back to THE LEAD. In our National Lead today, the mayor of Flint, Michigan, Karen Weaver, told us that a lot of passing the buck happened in her city. And e-mails newly released by Michigan Governor Rick Snyder, prove it.

[16:50:07]They show Governor Snyder had been informed about the dirty, smelly, toxic water in Flint as early as February of last year, but nothing was done.

And now the state of Michigan is finally taking some steps to undo some of the damage. With $28 million in emergency funding, though that money does nothing to alleviate the damage done to the health of the people of Flint.

Let's now bring in CNN chief medical correspondent, Dr. Sanjay Gupta who is in Flint, Michigan. Sanjay, how much lead is necessary to cause health dangers? And what are the effects -- how is this lead going to hurt the children of Flint?

SANJAY GUPTA, CNN CHIEF MEDICAL CORRESPONDENT: Yes, well, you know, what you'll hear from doctors and public health officials, Jake, you've probably heard this as there is no such thing as a safe amount of lead.

The reason they say that is because even small amounts depending on who the individual is can have some sort of health effect. But let me give you some of the numbers here to your question here.

When it comes to lead in the water, for example, they say cause for concern is at five parts per billion. Now, that's a very small amount. That's where they say cause for concern starts to come about.

Some of the testing come out of Virginia Tech was 158 parts per billion. There was a home that we visited yesterday, Jake, where the water tested at 13,000 parts per billion. I mean, I've never seen anything like it.

I have visited lead contaminated places around the world. This was the highest number I had seen. So that just gives you some context.

In terms of what it does to the body, kids are going to be more at risk than adults because their bodies are still developing. Lead is a heavy metal. It gets in and think of it sort of gumming up the machinery of cells.

Cells cannot function the way they used to so kids may have developmental delays, cognitive delays. When it comes to adults may have things like high blood pressure, miscarriages, joint pain. It could be a variety of things.

Lead just stays in the system and is irreversible because of that. What I think is frustrating as well, Jake, the symptoms could appear now. They could appear years from now. You just don't know.

TAPPER: Dr. Sanjay Gupta, thank you so much. Appreciate it.

A former Russian spy poisoned with radioactive material. Now a brand new investigation says his murder was probably approved by Vladimir Putin himself, but will Putin be punished? That's next.

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[16:56:32]

TAPPER: Welcome back to THE LEAD. I'm Jake Tapper. Topping our World Lead today is a tale that seems straight out of a spy novel. So audacious, so horrific it would have to be a work of fiction, but it's all too true.

An ex-KGB agent mysteriously poisoned while having tea at a London hotel, within days he was dead. It turns out that the plot to kill Alexander Litvinenko (ph) was likely approved at the kremlin's highest level by none other than Russian President Vladimir Putin.

That conclusion according to a report released this morning by investigators in the U.K. where Litvinenko was poisoned with polonium- 210 in the year 2006.

Let's get to CNN's international diplomatic editor, Nic Robertson, who is live in London. Nic, what do investigators believe was the motive beyond the fact that he was an ex-KGB spy?

NIC ROBERTSON, CNN INTERNATIONAL DIPLOMATIC EDITOR: Yes, sure, one of the things, Jake, was that he was very critical of Putin. He moved to U.K. in the year 2000. And he alleged such things as the big apartment bombings in Moscow in 1999 that allowed Putin to go to war in Chechnya where really a put-up job by the state.

There was that. That was when he was talking about that that was big explosive news. We kind of know about it a little more now, but that was a big deal at the time. He was also helping the British intelligence services unraveled the Russian criminal mafia that were operating clandestinely in the U.K.

So there were a number of reasons that Putin might have a good, strong need, if you will, to silence him.

TAPPER: And something also about alleging that Putin is a pedophile?

ROBERTSON: There were some of that too. His criticism of Putin was very strong. And, you know, one of the witnesses in this report that came out, unnamed witness who spoke to one of the alleged killers.

The alleged killer said, we've been told not to shoot him, but poison him to send a strong message to the others. So this was a man who was not a friend to President Putin in any shape or form.

TAPPER: So but is there evidence linking this to Putin directly?

ROBERTSON: There's no smoking gun. There's a lot of, if you will, circumstantial evidence. A lot of things the investigation points to. The polonium-210 used to kill him could have only been made in a nuclear reactor, reactors in Russia are under the control of the Russian state.

But for the poison to get out of this sort of atomic energy agency then into the hands of the intelligence services would need to be done by somebody who was overarching and above both of those.

Now, in the sort of back covering way that bureaucracy works in Russia the assessment is that could have only been done by Putin. He has a track record of other critics being apparently silenced by being killed. So there's a lot of other details as well, but that's the principal one.

TAPPER: Nic, quickly if you could, have the Russians responded to this?

ROBERTSON: Sure. The Foreign Ministry is saying, look, this is politically motivated by the British government. There was some secret details that weren't made public in this inquiry, that was because of association with the British intelligence services.

But they're really pouring cold water on it. They're not about to hand over the alleged killers. The alleged killers themselves are saying this is not true, we're innocent.

TAPPER: I guess we expected that. Nic Robertson, thanks so much.

That's it for THE LEAD. I'm Jake Tapper turning you over to one Mr. Wolf Blitzer in a place next door to me called "THE SITUATION ROOM." Thanks for watching.